A sample of 20 students who had recently taken elementary st

A sample of 20 students who had recently taken elementary statistics yielded the following information on brand of calculator owned. (T = Texas Instruments, H = Hewlett Packard, C = Casio, S = Sharp):

(a) Estimate the true proportion of all such students who own a Texas Instruments calculator.
(b) Of the 6 students who owned a TI calculator, 3 had graphing calculators. Estimate the proportion of students who do not own a TI graphing calculator.

Solution

a. 10/20 = .5

b. 16/20 = .8